摘要
利用堇青石为主晶相的微晶玻璃，高频损耗小，成功地研制了一种介电常数ε＝7．2±0．2，介电损耗tgδ＜1．5×10－4（制试频率＞1GHz）的微波材料.采用X射线衍射分析、扫描电镜、物理性能和电性能测试等技术，研究了该种玻璃晶化过程中的密度变化、晶相转变、以及电性能与晶相组成和结构的关系．
Glass ceramics with α-cordierite(2MgO.2Al2O3.5SiO2) as mam crystal phase, having low dis-sipation factor in high frequency range, are excellent materials for microwave substrates. However,the dielectric constant of the inaterial is not high enough for some applications. Recently, a novel glass ceramic witll dielectric constant higher than 7.0 and dissipation factor lower than 1.5×10-4(in the frequency range > 1GHz) was developed. The density changes and the expansion -shrinkage behaviour during crystallization process of the material were measured. The relationship between electric properties and composition and micro-structure of the glass-ceramics was studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and electric property testing. The results show that: (1) The changes of the density and volume of the materials during heat-treatment are caused by crystal phase transition. It's possible to avoid the sample from cracking during heat-treatment by selecting suitable heat-treated cycle.(2) The volume ratio of α-cordierite to MAT,the two main crystal phases in the glass-ceramic, mfluence the dielectric constant of the material.Furthermore, the more developed crystal grain is of benefit to increasing of dielectric constant.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
1997年第4期477-481,共5页
Journal of Inorganic Materials
关键词
微晶玻璃
晶化
介电性能
玻璃晶化
glass-ceramics, crystallization process, dielectric property
